Neurostimulation systems are devices that generate electrical pulses and deliver the pulses to nerve tissue to treat a variety of disorders. Spinal cord stimulation (SCS) is an example of neurostimulation in which electrical pulses are delivered to nerve tissue in the spine for the purpose of chronic pain control. Other examples include deep brain stimulation, cortical stimulation, cochlear nerve stimulation, peripheral nerve stimulation, vagal nerve stimulation, sacral nerve stimulation, etc. While a precise understanding of the interaction between the applied electrical energy and the nervous tissue is not fully appreciated, it is known that application of an electrical field to spinal nervous tissue can effectively mask certain types of pain transmitted from regions of the body associated with the stimulated nerve tissue. Specifically, applying electrical energy to the spinal cord associated with regions of the body afflicted with chronic pain can induce “paresthesia” (a subjective sensation of numbness or tingling) in the afflicted bodily regions. Thereby, paresthesia can effectively mask the transmission of non-acute pain sensations to the brain.
Neurostimulation systems generally include a pulse generator and one or more leads. The pulse generator is typically implemented using a metallic housing that encloses circuitry for generating the electrical pulses, control circuitry, communication circuitry, a rechargeable battery, etc. The pulse generation circuitry is electrically coupled to one or more stimulation leads through electrical connections provided in a “header” of the pulse generator. Typically, conductors in the leads carry the electrical pulses from a longitudinal series of annular terminals which are inserted into the header to a longitudinal series of stimulation electrodes implanted at the tissue site.
Pulse generators are preferably small to limit patient trauma and discomfort. Similarly, smaller headers used in such pulse generators are also desirable. In some circumstances, however, the overall length of the headers may be determined by the number and longitudinal spacing of the electrical connections coupling the terminals to wires coupled to the electrical circuitry within the pulse generator. It is desirable to reduce the size and spacing of the electrical connections so that either more conductors may be used or the size of the header may be reduced.
Furthermore, the placement of the electrical connectors in such a header can be unduly difficult especially when the electrical connectors are small. It is also desirable to maintain a watertight seal which will keep body fluids out of the header and between the electrical/mechanical interface of individual electrical circuits or connections.